Berastagi (Around 2 hours from Medan)
A cool, elevated town at the base of two volcanoes- Gunung Sibayak and Gunung.
A great break away from the heat for a weekend. A local bus leaves Medan every hour if you are brave (it was an exciting trip to say the least) otherwise you will need to hire a driver to take you there.

Climbing Gunung Sibayak takes around 3 hours and is well worth the climb. You can descend into the crater of the volcano where there are sulphuric off shoots and bubbling water all over. Bring a jacket! On the climb down you can rest your weary legs in the hot pools that are half way down. Well maintained and only around US 30c entry.

Accommodation is very basic- no hot water, simple and relatively clean rooms for around Rp. 50 000 (US$5)